Absence of pork-like insulin in guinea pig tissues

By using a technique for concentrating insulin 100-fold from tissue extracts with 75-95% recoveries, we earlier failed to detect pork-like insulin in guinea pig tissues and thus were unable to confirm reports from the National Institutes of Health that these tissues contain a pork-like insulin at concentrations averaging 1 ng/g. This difference could have been due to differences in strains of guinea pigs studied or in the species specificities of the antisera used for radioimmunoassay. In the current study, tissue extracts from both NIH and Hartley guinea pigs were assayed with three antisera routinely used in our laboratory and one antiserum that had been used in the National Institutes of Health laboratory. We observed that pork-like insulin in tissues from both strains of guinea pigs as determined with the four antisera is less than 0.02 ng/g. We therefore conclude that is is unlikely that nonpancreatic guinea pig tissues contain or synthesize a peptide resembling pork or other non-guinea pig mammalian insulin.